PDA

View Full Version : Life Expectancy of Wheels?


Chief
06-19-2006, 02:13 PM
First some background information. I am a 68-year old, 162 lb rider who is pretty competitive for his age but clearly not the strongest rider who ever came down the pike. I average about 9,000 miles of hilly riding a year. In the last three years I have cracked three rear rims--cracks emanating from the the drive-side spoke holes. The first set of wheels were Velomax (now Easton) Ascent II that lasted nearly 7,000 miles. Because a friend also cracked his Ascent II wheels, I decided to go custom. A well known wheel builder (frequently noted on this forum) built a set of wheels with 32 hole DT RR 1.1 rims, DT 240s hubs and 3X DT Super Comp Spokes for me. The rear wheel lasted about 8,500 miles before I noticed cracks emanating from three neighboring spokes holes on the drive side. I had the wheel rebuilt using the same but new components. Today, after 5,600 miles I noticed cracks again emanating from a drive-side spoke hole. In each case the inspection of the rim was precipitated by the wheel being ever so slightly out of true--not enough worth correcting.

Questions:
What is the life expectancy of set of good wheels?
Is it 6-7 thousand miles that I seem to be getting?
If it is significantly greater, then what am I doing wrong other than riding?

Thanks for your input.

Erik.Lazdins
06-19-2006, 02:17 PM
I have 16,000 so far on my Eurus which are ridden over fields, curbs. Solid, true, no problems - Knock on wood

Marcusaurelius
06-19-2006, 02:21 PM
First some background information. I am a 68-year old, 162 lb rider who is pretty competitive for his age but clearly not the strongest rider who ever came down the pike. I average about 9,000 miles of hilly riding a year. In the last three years I have cracked three rear rims--cracks emanating from the the drive-side spoke holes. The first set of wheels were Velomax (now Easton) Ascent II that lasted nearly 7,000 miles. Because a friend also cracked his Ascent II wheels, I decided to go custom. A well known wheel builder (frequently noted on this forum) built a set of wheels with 32 hole DT RR 1.1 rims, DT 240s hubs and 3X DT Super Comp Spokes for me. The rear wheel lasted about 8,500 miles before I noticed cracks emanating from three neighboring spokes holes on the drive side. I had the wheel rebuilt using the same but new components. Today, after 5,600 miles I noticed cracks again emanating from a drive-side spoke hole. In each case the inspection of the rim was precipitated by the wheel being ever so slightly out of true--not enough worth correcting.

Questions:
What is the life expectancy of set of good wheels?
Is it 6-7 thousand miles that I seem to be getting?
If it is significantly greater, then what am I doing wrong other than riding?

Thanks for your input.


Well to begin with you shouldn't be getting cracks near the spoke holes. I am not sure if you got a bad batch of rims or there was too much tension on the spokes. I usually check my spoke tension every couple of months with a spoke tension checking tool. Wheels last until the rim sidewalls wear out. Mavic has built a wear groove into some of their rims now. Hubs will last a very long time if you repack them with grease every 4-5 months especially if you ride in wet weather. Of course rims wear out much faster if you ride in tropical monsoon weather often.

vaxn8r
06-19-2006, 03:09 PM
I've worn out tandem rims as you describe...emanating from spoke holes. But I attribbuted that to a tandem team riding OP's. It would seem the spoke tensions may be too high but having the same problems with prebuilts and "custom"? That seems weird. Are you sure your weight isn't 162kg? ;)

Usually my wheels wear out from the braking surface of the rims...riding in the crud here in PNW.

Fixed
06-19-2006, 03:50 PM
bro when something starts talkin to me and complaining it needs to be heard . i.m.h.o.
cheers

ergott
06-19-2006, 03:52 PM
A good indication you are getting you money's worth is when you need to replace the rims because the brake track is worn out. There are many reasons this might not be the case and some of them are the rider, but most are the builder. Component selection and assemply methods are very important. Not every builder uses the same methods.

ada@prorider.or
06-19-2006, 03:58 PM
chief front and back?

i now you mentioned only rear

seems to me to high spoke tension

Chief
06-19-2006, 04:05 PM
chief front and back?

Cracking is only with the rear wheel. The cracks occur in pairs--one crack emanating from each side of the spoke hole--and always on the drive side. These rims have eyelets which I assume would reduce the tendency for cracking. The picture below was from the earlier failure, but is typical of the current failure.

gone
06-19-2006, 04:10 PM
I usually check my spoke tension every couple of months with a spoke tension checking tool.
Forgive a series of stupid questions and feel free to redirect me to somewhere to look it up but what's a reasonable spoke tension? I assume they're different for drive/non-drive but also for different rim materials, lacing patterns, spoke types?

After truing a wheel, I usually ping the spokes looking for any that sound significantly looser or tighter than the rest but who knows, over time I may be gradually tightening them way tighter than they should be, albeit uniformly.

ada@prorider.or
06-19-2006, 05:27 PM
Cracking is only with the rear wheel. The cracks occur in pairs--one crack emanating from each side of the spoke hole--and always on the drive side. These rims have eyelets which I assume would reduce the tendency for cracking. The picture below was from the earlier failure, but is typical of the current failure.
thanks
can you show the spoking pattern on the drive side
and does the nipple fits good in the eyelet
has it a round head or flat and how is the outside head
(inside of the rim) LOOKING?
in otherwords does the nipple has a perfect seating?

cpg
06-19-2006, 05:43 PM
Maybe it's those Texas roads? It seems like you're wheels are wearing out prematurely. Sounds like too much spoke tension but that's a guess. You're not hucking this thing are you? Are you running 10 speed Campy? They render a handbuilt wheel with a lot of dish. Probably too much. Why the industry sticks with 130mm rear spacing is dumb.

Curt

Jeremy
06-19-2006, 06:07 PM
These rims have eyelets which I assume would reduce the tendency for cracking.


Eyelets on lightweight rims often increase the likelihood of cracking. The reason for this is simple. Relatively, eyelets weigh quite alot, so to make a light rim with eyelets, the wall thickness of the rim has to be very thin. Older RR1.1 rims have single eyelets. The newer version has double eyelets, this transfers load over a larger area but also adds weight.

Jeremy

keno
06-19-2006, 07:06 PM
I can only speak to the Velomax/Easton wheels, which I believe employ unusually high spoke tension.

keno

Kahuna
06-19-2006, 07:42 PM
Oh brother. I just ordered a similar set of wheels from unsaid well-known wheelbuilder. Assembly date is scheduled for Wednesday and I thinks I'm going to put in a change request.

Recently I've seen a number of messages on other forums from people reporting DT RR1.1 rims cracking around the eyelets, just like you describe. The problem seems to be endemic to the rim.

I understand DT has since changed the design on the 32h model rim and they're now using double eyelets. The change adds a fair amount of weight to the rim but for now they're still calling them RR1.1s. The 28h model still uses the single eyelet design. I'm not sure if the problem occurs on them as well however, one would think so.

-K

atmo
06-19-2006, 08:51 PM
chief-issimo
i got your email. i have personally used many dt rims
built with all the dt parts,and have sold many more.
all are/were assembled by your guy. thusfar there
have been no cracking like your pic. fwiw, all of
my wheels are 28 f/r, radial front and 2x rear atmo.

mike p
06-19-2006, 08:58 PM
I used to get the exact same type cracking pictured on older mavic reflex rims. No such problems on open pro's. Happened on rear only 32 spoke.

Mike

shinomaster
06-19-2006, 08:58 PM
Hey Chief. That looks like shiit! Get an open pro, or a proton back wheel.

Chief
06-19-2006, 09:05 PM
chief-issimo
i got your email. i have personally used many dt rims
built with all the dt parts,and have sold many more.
all are/were assembled by your guy. thusfar there
have been no cracking like your pic. fwiw, all of
my wheels are 28 f/r, radial front and 2x rear atmo.

Thanks for the reply. Glad to hear you have had no cracking. Mine are 32 f/r laced with 2x on the front and 3x on the rear, but I can't believe this is the difference.

marle
06-20-2006, 09:18 AM
Congratulations. You got 4k more miles than I got from a wheelset built by the famous wheel builder.

Now when I get wheels I think about some facts - (1) factory wheels are designed by engineers (2) factory wheels are tested repeatly over long periods of time (3) factory wheels are built under a controlled production enviroment (4) there is a warranty.

ergott
06-20-2006, 10:00 AM
Congratulations. You got 4k more miles than I got from a wheelset built by the famous wheel builder.

Now when I get wheels I think about some facts - (1) factory wheels are designed by engineers (2) factory wheels are tested repeatly over long periods of time (3) factory wheels are built under a controlled production enviroment (4) there is a warranty.

(5) I'm sure noone has ever had problems with factory wheels.

alancw3
06-20-2006, 10:59 AM
i had a similar problem about thirty years ago with a rear wheel. a very knowledgable wheel builder told me that it was a classic case of excess spoke tension. like when i brought a rear spoke on the cog side the wheel would go out of ture by like 3/4rds of an inch. actually he told me that a correctly tensioned 36 hole wheel should almost stay completely true if you break a spoke. i didn't believe him. well a couple of months ago i heard a snap on the rear wheel of my vintage bob jackson (like i ran over a nail or something). looked at the wheel and tire was fine. well i rode that bike another couple of times before doing a cleaning and low and behold a rear cog side spoke was broken. i couldn't believe it. i mean the wheel was still perfectly true! i guess that builder new what he was talking about after all.

11.4
06-20-2006, 11:17 AM
I've run into this problem on a variety of prebuilt wheels and customs. In particular, I tended to break Mavic Reflexes (only in the CD finish, not the silver ones) and Ksyrium SL tubular rims (though perhaps because those were my most commonly ridden rims). That's one custom wheel type, one prebuilt machine wheel type. I had the problem with two different well-known builders plus my own, and with two different versions of the Ksyriums. And interestingly, I had the problem both on track and road. I've laced my own wheels to a wide range of tensions and had rim breakage at all tensions from 75% of Mavic recommendation up to 130%.

Keeping a close eye on rims, I've noticed that non-anodized rims have never given me trouble (or given trouble to those who I build for). And non-ferruled rims have never given trouble. (These comments apply to both tubular and clincher rims, for whatever that's worth -- they ultimately deal with the same mechanical issues.)

Having the problem on the track was an interesting observation point to consider. I can't blame rough roads there. Some riders broke wheels, others could ride the same wheel with impunity. What I did notice was that riders with the hardest (or most frequent) jumps combined with anything but very light weight tended to have the biggest problems. I also noticed that one typically developed a single cracked ferrule hole, which then zippered out into multiple cracks. I actually tried riding two rims with single cracked holes to see how they developed (both were track training wheels). Interestingly, the cracks both times progressed counterclockwise from the original hole (not in both directions as one might expect).

If you look at the rim in action, it basically gets flexed slightly and spoke tension is released on it as it reaches the bottom of its revolution. Then as it moves off that point, spoke tension returns and the rim flexes back into position. These aren't big differences (at least I tried sitting on a bike and measuring spoke tension at different points and didn't get a lot of difference). But if you do a hard jump, you're putting a lot of leading pressure into the spokes just before the contact patch, partly because the spokes just ahead of them are detensioned and not carrying the load and partly because your spokes and rims will spread load in most parts of the wheel, but not where the ground contact prevents the stress from spreading. (Put your front wheel against a wall, stand on the pedals, and measure spoke tension on the rear wheel and you'll see a bit of what I mean. Have someone else do the tension measurements, of course.) This behavior causes momentary point loading and if you do it very hard, you can get failure in a weaker rim. I think this is what's happening.

Ferrules definitely are a questionable advance in rim design. As was pointed out above, to compensate for ferrule weight the rim extrusion is lightened (or alternatively, ferrules were added to make up for lighter rim extrusions, which I think was actually the historical order of things). Note also that the hole actually has to be bigger to accommodate not just a nipple but also the wall of the ferrule. In theory that ferrule spreads the pressure of the nipple over a larger area, but most ferrules create local wedge-shaped point loads at the hole so they actually exacerbate the problem. Older ferruled rims had big flat ferrule bottoms, whereas newer rims have bases shaped to fit the spoke nipple and are narrower in pursuit of weight savings. Note that numerous machine-built wheels use very high tension but dispense with ferrules. I suspect there's a message there.

I don't think radial spoking has much to do with this one way or the other, since at the rim there's not much difference in exit angle for the nipple whether you're laced 0X or 3X. A couple of us have examined just over 170 broken radial wheels at this point to understand whether radial spoking is really a problem, and are working on write-ups both for hub breakage and for rims. The short version for rims is ... no evidence it's correlated.

In the end, all I can determine is that the one correlating factor is a 150+ pound rider doing hard sprints, intervals, jumps, whatever. This seems to create a local loading just in advance of the contact path that imposes more stress than many rims are prepared for. This explanation would also explain why spoke tension per se doesn't make too much difference, because tension is determined locally independent of overall spoke tension (spoke breakage might be a different issue, but we didn't see that either with modern spokes).

Apologies for the long-winded post. Hope this helps.

atmo
06-20-2006, 11:27 AM
Note that numerous machine-built wheels use very high tension but dispense with ferrules. I suspect there's a message there.

thank you.
also please note that nearly all factory built wheels
use rims that are so incredibly over-designed and
bomb-proof that the only purpose the spokes serve
is to keep the hub separated from the rim. as was once
noted in that seminal dufour interview (http://www.europastar.com/europastar/magazine/article_display.jsp?vnu_content_id=1000476650) , "... everything
is designed to be made on a machine."

flydhest
06-20-2006, 11:29 AM
anyone have a reference for recommended tensions for different rims?

zeroking17
06-20-2006, 11:46 AM
thank you.
also please note that nearly all factory built wheels
use rims that are so incredibly over-designed and
bomb-proof that the only purpose the spokes serve
is to keep the hub separated from the rim. as was once
noted in that seminal dufour interview (http://www.europastar.com/europastar/magazine/article_display.jsp?vnu_content_id=1000476650) , "... everything
is designed to be made on a machine."

I'm unsure of your intent in referring to that Dufour quotation in this context (which I assume to be "machine- vs hand-built wheels"). I took Dufour to be making a point about the limitations of machine-built objects, the necessary absence of the human touch. (I attached the larger quotation below. Emphasis added.)

As such, there seems to be a certain tension between your emphasis on the inherent value of handcrafted frames and the simultaneous valorization of machine-built wheels. Am I reading you right?


Edit: On re-reading, I see that you're likely making a distinction between factory-built (and not necessarily machine-built) wheels and hand-built wheels. I know that you use both Campy-built wheels and wheels from "hand"-builders. So my characterization may be misleading--but I'm not certain. That's why I'm asking.


Dufour...
I go to extremes in life to do the best I can. In today’s modern movement, born with the 'renaissance’ of the mechanical watch, even in the best of these movements, everything is designed to be made on a machine. Please understand me when I say that even if the hand of man has its role to play, the architecture itself of the movement, like the design of its component parts, is created with machine manufacturing in mind. However, a machine is incapable of making bridges with rounded corners as are done by hand in my atelier. In the 'Simplicity’ watch, there is the enormous added value of being totally handcrafted. There is a certain emotional attraction of knowing that a skilled hand, using traditional tools, has created a personal timepiece. It has its own internal vibration. It is something living and unique…it is poetry from the hand.

atmo
06-20-2006, 11:59 AM
I'm unsure of your intent in referring to that Dufour quotation in this context (which I assume to be "machine- vs hand-built wheels"). I took Dufour to be making a point about the limitations of machine-built objects, the necessary absence of the human touch. (I attached the larger quotation below. Emphasis added.)

As such, there seems to be a certain tension between your emphasis on the inherent value of handcrafted frames and the simultaneous valorization of machine-built wheels. Am I reading you right?


nah and yeah -
i was refering to that fact that wheelbuilders seldom
use the material that factory wheels are made from,
and that you probably couldn't trust a factory made
wheel made with dt 240s hubs, rr 1.1 rims, and what-
ever the fancy db spokes are called.
my post wasn't frame-centric.


edit - yeah. you're on the mark with your edit!.
btw, i do not use campagnolo hubs, feeling that
they have the wrong flange with for modern
drive trains. otoh, if they would separately sell
the straight pull hubs that go on their neutron,
ouch-eee-mama atmo.

zeroking17
06-20-2006, 12:04 PM
nah and yeah -
i was refering to that fact that wheelbuilders seldom
use the material that factory wheels are made from,
and that you probably couldn't trust a factory made
wheel made with dt 240s hubs, rr 1.1 rims, and what-
ever the fancy db spokes are called.
my post wasn't frame-centric.


OK, I get it.

P.S. And my post was neither frame- nor wheel-centric. It was more about the approach that a crafstman takes to making something--be it a frame, a wheel, a basket, or a video. In all cases, the song remains the same, and the act of creation is abstracted from the object being created.


.

zeroking17
06-20-2006, 12:06 PM
<snip> ouch-eee-mama


I couldn't have said it better myself.


..

atmo
06-20-2006, 12:10 PM
OK, I get it.

P.S. And my post was neither frame- nor wheel-centric. It was more about the approach that a crafstman takes to making something--be it a frame, a wheel, a basket, or a video. In all cases, the song remains the same, and the act of creation is abstracted from the object being created.


.

i agree. i didn't want to go there because that is
turf for the wheelbuilders here to defend. my
comments and references were indeed ambiguous
and abstract - because it's lunchtime - and i need
to wash all this dried flux from my cuticles.

zeroking17
06-20-2006, 12:13 PM
<snip> because it's lunchtime - and i need
to wash all this dried flux from my cuticles.

Wouldn't the "internal vibration" take care of that?


...

ada@prorider.or
06-20-2006, 12:17 PM
Keeping a close eye on rims, I've noticed that non-anodized rims have never given me trouble (or given trouble to those who I build for). And non-ferruled rims have never given trouble. (These comments apply to both tubular and clincher rims, for whatever that's worth -- they ultimately deal with the same mechanical issues.)

Marcusaurelius
06-20-2006, 12:41 PM
anyone have a reference for recommended tensions for different rims?


"The Art of Wheelbuilding" by Gerd Schraner will give you some guidelines. If not, I just send an email to the manufacturer and you will usually get an email back in a day or two. I sent one to Velocity and they answered back in a day with the recommended tension for the rim.

marle
06-20-2006, 01:42 PM
A wheel from a factory is still an act of human creation.

gone
06-20-2006, 02:02 PM
Congratulations. You got 4k more miles than I got from a wheelset built by the famous wheel builder.

Now when I get wheels I think about some facts - (1) factory wheels are designed by engineers (2) factory wheels are tested repeatly over long periods of time (3) factory wheels are built under a controlled production enviroment (4) there is a warranty.
OK, here are some facts.

1. I've got 2 sets of Mavic SSC SL's, 2004 & 2005 models.
2. I've had the rear on the 2004 set crack (in multiple places) at the spoke heads two times, rebuilt both times with new rims.
3. I've had the rear on the 2005 set crack (in multiple places) a the spoke head and rebuilt once. I also had a weld break inside the freehub.
4. Yes, they were fixed under warranty.
5. I've had custom wheels repaired without charge also.

BTW, though not the lightest guy on a bike, I'm no clydesdale, I weigh 170-174 lbs.

dgauthier
06-20-2006, 02:06 PM
"The Art of Wheelbuilding" by Gerd Schraner will give you some guidelines. (. . . ) I sent (an e-mail) to Velocity and they answered back in a day with the recommended tension for the rim.

1. And the recommended tension, and the Velocity rim in question, was . . . ?

2. Very vague info on spoke tension (why is it always so vague?) is available on the super-secret Mavic "extranet" web site, www.tech-mavic.com. Use the name: mavic-com, and the password: dealer (thanks Jeff Weir, for posting the info to this forum). Under Products/Road and Triathlon/Rims you'll find "SpokeTension.pdf", where Mavic suggests a final tension of 90-110 daN. Though they don't mention a specific rim, an Open Pro is clearly shown in the accompanying photos. Further seaching of the tech-mavic site will yield recommended spoke tensions for several of their pre-built wheelsets as well, iirc.

3. Don't Gerd Schraner and Jobst Brandt, in their respective books, recommend using the highest spoke tension the rim can take without collapsing? (Or am I reading them wrong?) If one follows their instructions exactly, one certainly ends up with waaayyy more tension than 100 daN on an Open Pro - enough to crack a rim eventually. Could this be part of the problem?

ergott
06-20-2006, 03:04 PM
edit - yeah. you're on the mark with your edit!.
btw, i do not use campagnolo hubs, feeling that
they have the wrong flange with for modern
drive trains. otoh, if they would separately sell
the straight pull hubs that go on their neutron,
ouch-eee-mama atmo.

I'm curious why you say this. The drive side flange is no further toward center than other Campagnolo compatable hubs. The famous DT hub is about the same as well. They do not redish the rear hub when swapping the freehub bodies which puts them at a disadvantage when comparing them to Shimano specific hubs. I find the tension difference on DT hubs is no different than Campy hubs.

I do not agree that machine/factory wheels have any advantage over smaller operations. They are no more overbuilt than a properely designed component list a wheelbuilder could come up with. I've built wheels around Velocity Aerohead rims including the offset rear that were 1430g and still were 32 spoke 3 cross. That rim and spoke combination will rival any "factory" wheel in durability and stiffness. If the weight barrier were moved to 1500g to 1550g which compares to many of the finest "factory" wheels with aluminium rims and one could easily accomodate even the heavest riders.

The bottom line is that right company/wheelbuilder can both make the finest wheels out there. They can also be responsible for some of the duds out there as well.

ergott
06-20-2006, 03:08 PM
1. And the recommended tension, and the Velocity rim in question, was . . . ?

2. Very vague info on spoke tension (why is it always so vague?) is available on the super-secret Mavic "extranet" web site, www.tech-mavic.com. Use the name: mavic-com, and the password: dealer (thanks Jeff Weir, for posting the info to this forum). Under Products/Road and Triathlon/Rims you'll find "SpokeTension.pdf", where Mavic suggests a final tension of 90-110 daN. Though they don't mention a specific rim, an Open Pro is clearly shown in the accompanying photos. Further seaching of the tech-mavic site will yield recommended spoke tensions for several of their pre-built wheelsets as well, iirc.

3. Don't Gerd Schraner and Jobst Brandt, in their respective books, recommend using the highest spoke tension the rim can take without collapsing? (Or am I reading them wrong?) If one follows their instructions exactly, one certainly ends up with waaayyy more tension than 100 daN on an Open Pro - enough to crack a rim eventually. Could this be part of the problem?


Max tension that I know of (in kg which many tensiometers use)

Velocity 120kg (some use more)
Mavic 110kg
Zipp 100kg minimum
DT 100kg

These are numbers I've received from either manufacturers or distributers. In general, I use 100kg for ferruled, 110kg for Zipp and 120kg for Velocity (non ferruled).

dgauthier
06-20-2006, 03:43 PM
I'm curious why you say this. The drive side flange is no further toward center than other Campagnolo compatable hubs.

Not to speak for e-atmo, but I thought the big issue with Campy hubs was the *non* drive side flange was too far *away* from center, producing a greater tension imbalance between the drive and non-drive sides. Since DT and Shimano hubs have the non-drive flange closer to the center, the non-drive side tension can be higher, supposedly reducing the imbalance and producing a more durable wheel (though at the expense of overall lateral strength).

Are you saying you do not find this to be an issue? Do tell, please - inquiring minds want to know!

Thanks Ergott, for the spoke tension info! (I imagine you lifting some leather-bound tome onto a pedestal, and leafing through pages of dusty parchment. "Ah, here is it . . spoke tension . . .") And yes, 1.0 daN (decanewton) is equal to 1.019716 kgf (killogram-force), so the units are interchangeable at the precisions required for wheelbuilding.

Chief
06-20-2006, 04:43 PM
A closer inspection of my rim with a 10X loop reveals that there are cracks, of differing lengths, emanating from 7 of the 16 drive-side spoke holes. For the interested these occur at the following spoke holes: Taking the valve hole as the reference point and proceeding around the rim in the direction of forward rotation of the wheel (i.e., clockwise as viewed from the right side), they occur at 16.875*, 39.375*, 61.875*, 106.875*, 129.375*, 196.875*, and 241.875*. As a point of information, there are 22.5* between the drive side spoke holes (for that matter also between the non-drive spoke holes).

As an aside, you may wonder why I am so anal about this. First, of course is the most obvious--it is my rims that are cracking. :crap: Second, my area of technical expertise and my primary source of livelihood before retiring is fracture mechanics--the engineering discipline related to why and how structures fail by crack growth.

ergott
06-20-2006, 05:05 PM
Not to speak for e-atmo, but I thought the big issue with Campy hubs was the *non* drive side flange was too far *away* from center, producing a greater tension imbalance between the drive and non-drive sides. Since DT and Shimano hubs have the non-drive flange closer to the center, the non-drive side tension can be higher, supposedly reducing the imbalance and producing a more durable wheel (though at the expense of overall lateral strength).

Are you saying you do not find this to be an issue? Do tell, please - inquiring minds want to know!

Thanks Ergott, for the spoke tension info! (I imagine you lifting some leather-bound tome onto a pedestal, and leafing through pages of dusty parchment. "Ah, here is it . . spoke tension . . .") And yes, 1.0 daN (decanewton) is equal to 1.019716 kgf (killogram-force), so the units are interchangeable at the precisions required for wheelbuilding.

Let me get that book back out...
;) ;) ;)

I normally use Velocity rims because of the higher tension allowable. The offset rim further benefits this.

Just for your information:

These are the measurements for some Campy compatable hubs. They are from center to the right and left flanges.

CL - CR (in mm)
36.5 - 16.3 Campagnolo
32.6 - 16.6 DT
39.5 - 16.5 Tune
38.3 - 16.2 White Industries

You can't put the right flange any closer without interference issues. As long as the right side tension is within range of the rim specs and spokes do not go slack on the non drive side (read sufficient spoke count and tension) there is no problem with any of the hubs. There are plenty of wheels out there (some I've built ;) ) that are just fine with Campy hubs.

dgauthier
06-20-2006, 05:05 PM
my area of technical expertise and my primary source of lifelihood before retiring is fracture mechanics--the engineering discipline related to why and how structures fail by crack growth.

Chief, it would be interesting to measure the tension on your drive side spokes (especally before the rim fails further, as I would imagine tension is releasing as the cracks propogate.) As Ergott pointed out, the recommended tension for a DT rim is about 100 kgf. (A quick e-mail to DT might be in order to confirm this from "the horse's mouth."). Maybe your LBS could take a few spoke tension readings for you?

The consensus here seems to be that your wheel was built with too much spoke tension. I am not a wheel builder, but cycling is not rocket science, either. You're a relatively light rider, and imho, it would seem your rim failed prematurely. If a few measurements show that the wheel was built with a tension greater than what the manufacturer recommends, you might want to bring this to your wheel builder's attention. Most artisan builders take great pride in doing things right, and I would bet your builder would be only too happy to do right by you.

ergott
06-20-2006, 05:08 PM
discipline related to... crack growth.

That's funny on many levels!

Been to many plumber's conventions?

dgauthier
06-20-2006, 05:42 PM
CL - CR (in mm)
36.5 - 16.3 Campagnolo
32.6 - 16.6 DT
39.5 - 16.5 Tune
38.3 - 16.2 White Industries


Thanks again, Ergott. I was not aware that, although the DT hub does produce the most balanced bracing angles, the Campy hub is a good number two.

Thanks for putting it all in perspective. I'd bet my money (and life) on a nice Record or Chorus hub anytime. People seem to get all gooshy over their DT hubs, but frankly, DT's history of hub quality problems makes me think twice. (Hey - maybe Chief's wheels weren't built with too much tension after all, and it's the DT rims that are to blame. Who knows? Chief, I hope you get some measurements, and let us know how it turns out.)

Chief
06-20-2006, 06:32 PM
Chief, it would be interesting to measure the tension on your drive side spokes (especally before the rim fails further, as I would imagine tension is releasing as the cracks propogate.) As Ergott pointed out, the recommended tension for a DT rim is about 100 kgf. (A quick e-mail to DT might be in order to confirm this from "the horse's mouth."). Maybe your LBS could take a few spoke tension readings for you?

The consensus here seems to be that your wheel was built with too much spoke tension. I am not a wheel builder, but cycling is not rocket science, either. You're a relatively light rider, and imho, it would seem your rim failed prematurely. If a few measurements show that the wheel was built with a tension greater than what the manufacturer recommends, you might want to bring this to your wheel builder's attention. Most artisan builders take great pride in doing things right, and I would bet your builder would be only too happy to do right by you.

I'll try to get some measurements on Thursday and report back. However, from what I gather from 11.4, Jeremy and others, the spoke loads applied by the rider are significantly greater than the initial build tension and, therefore, it is unlikely that excessive initial spoke tension is causing the cracking, but rather the RR1.1 design. DT is now using a double eyelet rather than the initial single eyelet design that seems telling to me. DT has offered me a RR1.1 with double eyelets. We'll see how this goes.

To all those that have taken the time to respond, I am truly gratefull and impressed by the sum total of knowledge on this forum. This is one of the great things about this forum and I am thankful to Ben for making it available. We all own him a debt of gratitude. To all the responders to my post, "Thank you."

PS I'll keep you informed regarding the final resolution.

robg
06-21-2006, 10:32 AM
Chief,

Read the thread with interest. Last night while cleaning my ride I saw the same cracks you described on your rim on my rear DT 1.1 rims (non-drive side cracks). I had mine built by the same builder as you. This is the second rim, first replaced last summer both less than 5K miles. I've e-mailed the builder to see where we go from here. I'll be interested to get his take as I know he had been in contact with the company. Did you speak to the builder at all? He's a good guy and very well respected so I'm confident he'll stand behind the work. Interested to hear the outcome of your experience. Biggest drag on my part is I have to ride my back-up bike until this problem is resolved.

robg

ada@prorider.or
06-21-2006, 02:06 PM
. Biggest drag on my part is I have to ride my back-up bike until this problem is resolved.

robg
well then you lucky guy
there are tons of people who only have one bike

Chief
06-21-2006, 02:40 PM
That's funny on many levels!

Been to many plumber's conventions?

It try to keep my "plumber" concealed using bib shorts. :D

robg
06-21-2006, 07:37 PM
well then you lucky guy
there are tons of people who only have one bike

You're right, I am lucky, my primary ride is a Sachs! :beer:

Chief
06-22-2006, 02:51 PM
Chief, it would be interesting to measure the tension on your drive side spokes (especally before the rim fails further, as I would imagine tension is releasing as the cracks propogate.) As Ergott pointed out, the recommended tension for a DT rim is about 100 kgf. (A quick e-mail to DT might be in order to confirm this from "the horse's mouth."). Maybe your LBS could take a few spoke tension readings for you?

The consensus here seems to be that your wheel was built with too much spoke tension. I am not a wheel builder, but cycling is not rocket science, either. You're a relatively light rider, and imho, it would seem your rim failed prematurely. If a few measurements show that the wheel was built with a tension greater than what the manufacturer recommends, you might want to bring this to your wheel builder's attention. Most artisan builders take great pride in doing things right, and I would bet your builder would be only too happy to do right by you.


I measured the drive-side spoke tension using a Park Tension tool. Nine of the 16 spokes have a tension of 89 Kgf = 875 N = 88 daN and cracks occurred at 4 of the respective spoke holes; 2 of 16 spokes have a tension of 98 Kgf = 963 N = 96 daN with cracks occurring at all of these spoke holes; 2 of 16 spokes have a tension of 81Kgf = 796 N = 80 daN, cracks occurring at one of the spoke holes; 3 of 16 spokes have a tension of 73 Kgf = 716 N = 72 daN, no cracking occurred at these spoke holes. The current tensions in the spokes are less than the maximum recommended DT tension of 100 Kgf quoted by Ergott. Thus, excessive spoke tension doesn't appear to be responsible for cracking. The builder claimed that the initial spoke tensions did not vary by more than +/-5%. Clearly, the variation is now more than 5%, but this is not surprising because as I noted in my initial post the wheel was slightly out of true. (NB I am not sure when he quoted variaiton of 5%, whether he was referring to the meter reading or the actual tension--the latter depending nonlinearly upon the meter reading. If in fact he was quoting the meter reading as I believe he did, then they are still close to being within +/-5%.)

Chief
06-22-2006, 03:01 PM
Chief,

Read the thread with interest. Last night while cleaning my ride I saw the same cracks you described on your rim on my rear DT 1.1 rims (non-drive side cracks). I had mine built by the same builder as you. This is the second rim, first replaced last summer both less than 5K miles. I've e-mailed the builder to see where we go from here. I'll be interested to get his take as I know he had been in contact with the company. Did you speak to the builder at all? He's a good guy and very well respected so I'm confident he'll stand behind the work. Interested to hear the outcome of your experience. Biggest drag on my part is I have to ride my back-up bike until this problem is resolved.

robg

DT is going to replace my rim with a RR1.1 with double eyelets. All 32 hole RR1.1 rims sold in the USA will have double eyelets. The 28 hole RR1.1 will remain single eyelet, but likely with a recommended rider weight limitation. I am uncertain what the weight restriction will be, but at 162 lbs I was informed that I would be under it. While I have sent my builder emails, I have not talked to him directly, but plan to do so shortly.

That's all the news from San Antonio.

wasfast
06-22-2006, 05:39 PM
Sorta going full circle, you initally asked what to expect in terms of wheel life. I don't ride as much as you but around 5K miles per year. I rode for 5 years in the 1970's and again the last 3 years. I'm yet to have a wheel "wearout" (thin rim from braking, eyelet failure, etc). I would be looking for a different rim than the DT's or Open Pro's based on your experience. BTW, I'm not lightweight (190lbs) and ride 50% of the time on my rain bike, 50% on the dry bike.

I do know there has been discussions about anodized, especialy hard anodized rims having more issues. This is more annecdotal but from a surface change standpoint, it may make some sense in terms of making the rim more brittle.

My current wheels have Mavic CXP22's(rain bike) and Rolf Prima Elan (dry bike).

I know some riders like Kerry Irons on Roadbikereview.com have 15K-20K miles on a single set of wheels of the traditional variety.

robg
06-22-2006, 06:04 PM
DT is going to replace my rim with a RR1.1 with double eyelets.

Chief,

Would you mind sharing contact info with me for DT? Is builder going to re-build the wheel? I've sent e-mails and left phone messages, but no reply. I remember he was on vacationlast year around this time.

robg

Chief
06-22-2006, 06:43 PM
Chief,

Would you mind sharing contact info with me for DT? Is builder going to re-build the wheel? I've sent e-mails and left phone messages, but no reply. I remember he was on vacationlast year around this time.

robg


Check your PM.

Fat Robert
06-22-2006, 06:48 PM
yo chief

I tried to post a thread on this, but the board is having some problems again.

can you think of any bike food that's tolerable when its 95+?

after sucking down a GU packet that had been in my jersey for four and a half hours on a 97 degree day, and just about hurling the crap up, I did the last hour of the ride without food rather than eat another one....

bike food sucks

hot bike food double sucks

catulle
06-22-2006, 07:17 PM
yo chief

I tried to post a thread on this, but the board is having some problems again.

can you think of any bike food that's tolerable when its 95+?

after sucking down a GU packet that had been in my jersey for four and a haf hours on a 97 degree day, and just about hurling the crap up, I did the last hour of the ride without food rather than eat another one....

bike food sucks

hot bike food double sucks

I ride with a BigMac in a Ziploc bag, atmo.

vaxn8r
06-22-2006, 07:19 PM
I ride with a BigMac in a Ziploc bag, atmo.
Mmmmmm...that sounds gooood!

catulle
06-22-2006, 07:22 PM
Mmmmmm...that sounds gooood!

Fries travel in a half bottle on the seat tube, iirc.

Chief
06-22-2006, 07:55 PM
yo chief

I tried to post a thread on this, but the board is having some problems again.

can you think of any bike food that's tolerable when its 95+?

after sucking down a GU packet that had been in my jersey for four and a haf hours on a 97 degree day, and just about hurling the crap up, I did the last hour of the ride without food rather than eat another one....

bike food sucks

hot bike food double sucks

Sorry, it's Chief not Chef. I wouldn't think of riding for 4-1/2 hours at 97*, but if I did it would probably be :beer:

wasfast
06-23-2006, 04:52 PM
Here's some information in this thread from Mark Mc which is pretty good technically about anodizing and aluminum cracks. He's a MechEng (as am I) but it's a concise opinion on the various rim treatments relative to OP and also the Swiss rims.

http://forums.roadbikereview.com/showthread.php?t=64224